The present invention relates to a tape cassette for stabilizing tape running.
This kind of tape cassettes is, as shown in FIG. 1 constructed in such a manner that a pair of tape hubs 2, 3 are arranged in a cassette body 1 divided into upper and lower portions. A magnetic tape 4 is wound around one hub, for example a hub 2, and is guided along a window portion 1a on the side surface of the cassette body 1 and taken up to the other hub 3. In this case, in order to guide the magnetic tape 4 along the window portion 1a, there are provided turning rollers 5, 6 at the tape feeding side from the hub 2 and at the tape taken-up side to the hub 3, respectively. In FIG. 1, reference numeral 7 is a pad for slidingly contacting the tape 4 with the head surface with a predetermined pressure when a magnetic head (not shown) is inserted from the window portion 1a.
With the use of such tape cassette, if the tape 4 wound around the hub 2 is not in proper alignment during feeding of the tape 4 to the hub 3 deflection will occur in the tape in the widthwise direction. This deflection can be regulated by the roller 5 but it cannot be removed completely, so that tape deflection will occur at the head surface, thereby producing a track shift and considerably deteriorating the tape characteristics at the time of recording and reproduction. Recently, this type of tape cassette has been considered for use with video tape wherein higher tape speed is required (4.8 cm/sec in a compact cassette) thereby causing deflection during tape running to cause more conspicuous distortions and level change particularly in a cassette tape having a narrow track width wherein an azimuth shift is often generated.